1. Field of the Invention
The present invention relates to a living polymerization method for polymerizing (meth)acrylic acid esters, epoxides or lactones using a metal porphyrin complex as a polymerization initiator and an organic aluminum compound having a bulky substituent group as a cocatalyst.
2. Description of the Prior Art
A method of preparing poly(methacrylate) having a uniform molecular weight (that is, having a narrow molecular weight distribution) using an aluminum porphyrin complex as a polymerization initiator has already been known (cf., J. Am. Chem. Soc., vol. 109, 4737 (1987); Japanese Patent Application Laid-Open No. 259008/1989; and Japanese Patent Application Laid-Open No. 259009/1989).
However, in the aforementioned type of method, the polymerization rate is not so high. For example, in the case of polymerization of methyl methacrylate, the polymerization ratio is 65% for the polymerization time of 0.5 hour, and 100% for 1 hour. Thus, the method is insufficient in productivity (cf., Japanese Patent Application Laid-Open No. 259008/1989).
Similarly, there has already been known a method in which polyether or polyester is prepared from epoxide or lactone, respectively, using an aluminum porphyrin complex as a polymerization initiator (cf., Macromolecules, vol. 14, 1166 (1981); Macromolecules, vol. 20, 3076 (1987)).
However, the polymerization rates of propylene oxide and 8-valerolactone are not so high, more specifically 80% for 3.3 hours, and 53% for 1.3 hours, respectively. Therefore, this method is also unsatisfactory in productivity.